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She sat down in a chair and listened to me.
Literal
She [topic-は] chair [in-に] sat [and-て] my talk [object-を] listened.
椅子に座る uses に for the location of resulting position — same に that marks 'place where someone exists' in 学校にいる. The座る ('sit') is itself a stative-resulting verb: the subject moves into the seated state. Note the use of 私の話を聞く ('listen to my story/talk') — 話 covers both 'a story being told' and 'what someone is saying,' so this can be 'listened to my story' or 'heard me out.' The て-form 座って links 'sat down' as a backdrop to the listening that follows.